With the development of technology, person computers such as desk top computers and note computers are widely used in daily life. In addition, with the rapid development of electronic communication, international e-commerce has experienced steady growth for quite a number of years and becomes a trend in today's business world. The person computers no longer meet requirements of e-commerce companies. Accordingly, developers develop various types of servers, such as rack servers, blade servers and upright servers for helping e-commerce companies to deal with e-commerce issues.